Class: OpenC3::WebSocketApi

Inherits:
Object show all
Defined in:
lib/openc3/script/web_socket_api.rb

Overview

Base class - Do not use directly

Direct Known Subclasses

CmdTlmWebSocketApi, ScriptWebSocketApi

Constant Summary collapse

USER_AGENT = 
'OpenC3 / v7 (ruby/openc3/lib/io/web_socket_api)'.freeze

Instance Method Summary collapse

Constructor Details

#initialize(url:, write_timeout: 10.0, read_timeout: 10.0, connect_timeout: 5.0, authentication: nil, scope: $openc3_scope, &block) ⇒ WebSocketApi

Create the WebsocketApi object. If a block is given will automatically connect/disconnect



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# File 'lib/openc3/script/web_socket_api.rb', line 24

def initialize(url:, write_timeout: 10.0, read_timeout: 10.0, connect_timeout: 5.0, authentication: nil, scope: $openc3_scope, &block)
  # $openc3_scope is only set inside the Script Runner / microservice
  # environment. Fall back to OPENC3_SCOPE (mirrors the Python client) so a
  # bare `ruby script.rb` doesn't send a nil scope that the server rejects.
  @scope = scope || ENV.fetch('OPENC3_SCOPE', 'DEFAULT')
  @authentication = authentication.nil? ? generate_auth() : authentication
  @url = url
  @write_timeout = write_timeout
  @read_timeout = read_timeout
  @connect_timeout = connect_timeout
  @subscribed = false
  if block_given?
    begin
      connect()
      yield self
    ensure
      disconnect()
    end
  end
end

Instance Method Details

#connect ⇒ Object

Connect to the websocket with authorization in query params



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# File 'lib/openc3/script/web_socket_api.rb', line 171

def connect
  disconnect()
  final_url = @url + "?scope=#{@scope}"
  @stream = WebSocketClientStream.new(final_url, @write_timeout, @read_timeout, @connect_timeout)
  @stream.headers = {
    'Sec-WebSocket-Protocol' => 'actioncable-v1-json, actioncable-unsupported',
    'User-Agent' => USER_AGENT
  }
  @stream.connect
end

#connected? ⇒ Boolean

Are we connected?

Returns:

  • (Boolean) 


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# File 'lib/openc3/script/web_socket_api.rb', line 183

def connected?
  if @stream
    @stream.connected?
  else
    false
  end
end

#disconnect ⇒ Object

Disconnect from the websocket and attempt to send unsubscribe message



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# File 'lib/openc3/script/web_socket_api.rb', line 192

def disconnect
  if connected?()
    begin
      unsubscribe()
    rescue
      # Oh well, we tried
    end
    @stream.disconnect
  end
end

#generate_auth ⇒ Object

Generate the appropriate token for OpenC3



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# File 'lib/openc3/script/web_socket_api.rb', line 206

def generate_auth
  if ENV['OPENC3_API_TOKEN'].nil? and ENV['OPENC3_API_USER'].nil?
    if ENV['OPENC3_API_PASSWORD']
      return OpenC3Authentication.new()
    else
      raise "Environment Variables Not Set for Authentication"
    end
  else
    return OpenC3KeycloakAuthentication.new(ENV['OPENC3_KEYCLOAK_URL'])
  end
end

#read(ignore_protocol_messages: true, timeout: nil) ⇒ Object

Read the next message with json parsing, filtering, and timeout support



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# File 'lib/openc3/script/web_socket_api.rb', line 52

def read(ignore_protocol_messages: true, timeout: nil)
  start_time = Time.now
  while true
    message = read_message()
    # Empty string is a normal end-of-stream signal when ActionCable / anycable-go
    # closes the WS. Treat it the same as nil so consumer `while (resp = api.read)`
    # loops exit cleanly instead of hitting JSON::ParserError on JSON.parse("").
    return nil if message.nil? || message.empty?

    begin
      json_hash = JSON.parse(message, allow_nan: true, create_additions: true)
    rescue JSON::ParserError
      # Defense-in-depth: treat malformed frames as end-of-stream rather than crashing.
      return nil
    end
    if ignore_protocol_messages
      type = json_hash['type']
      if type # ping, welcome, confirm_subscription, reject_subscription, disconnect
        if type == 'disconnect'
          if json_hash['reason'] == 'unauthorized'
            raise "Unauthorized"
          end
        end
        if type == 'reject_subscription'
          raise "Subscription Rejected"
        end
        if timeout
          end_time = Time.now
          if (end_time - start_time) > timeout
            raise Timeout::Error, "No Data Timeout"
          end
        end
        if defined? RunningScript and RunningScript.instance
          raise StopScript if RunningScript.instance.stop?
        end
        next
      end
    end
    return json_hash['message']
  end
end

#read_message ⇒ Object

Read the next message without filtering / parsing



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# File 'lib/openc3/script/web_socket_api.rb', line 46

def read_message
  subscribe()
  return @stream.read
end

#subscribe ⇒ Object

Will subscribe to the channel based on @identifier



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# File 'lib/openc3/script/web_socket_api.rb', line 95

def subscribe
  unless @subscribed
    # Token is part of the identifier so it surfaces as params[:token] in
    # ApplicationCable::Channel#authenticate_subscription! — ActionCable
    # ignores `data` on `subscribe` commands.
    @identifier['token'] = @authentication.token(include_bearer: false)
    json_hash = {}
    json_hash['command'] = 'subscribe'
    json_hash['identifier'] = JSON.generate(@identifier, allow_nan: true)
    @stream.write(JSON.generate(json_hash, allow_nan: true))
    @subscribed = true
    wait_for_subscribed()
  end
end

#unsubscribe ⇒ Object

Will unsubscribe to the channel based on @identifier



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# File 'lib/openc3/script/web_socket_api.rb', line 138

def unsubscribe
  if @subscribed
    json_hash = {}
    json_hash['command'] = 'unsubscribe'
    json_hash['identifier'] = JSON.generate(@identifier, allow_nan: true)
    @stream.write(JSON.generate(json_hash, allow_nan: true))
    @subscribed = false
  end
end

#wait_for_subscribed ⇒ Object

Block until the server confirms the subscription. ActionCable / anycable-go process 'subscribe' and 'message' commands as independent RPCs, so an action (add/remove) written immediately after subscribe can reach StreamingChannel#add before the subscription's broadcaster exists, where it is silently dropped (a no-op) and no data ever streams. Waiting for confirm_subscription guarantees the broadcaster is ready before any action is written.



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# File 'lib/openc3/script/web_socket_api.rb', line 117

def wait_for_subscribed
  while true
    message = @stream.read
    raise "WebSocket closed before subscription was confirmed" if message.nil? || message.empty?

    json_hash = JSON.parse(message, allow_nan: true, create_additions: true)
    case json_hash['type']
    when 'confirm_subscription'
      return
    when 'reject_subscription'
      raise "Subscription Rejected"
    when 'disconnect'
      raise "Unauthorized" if json_hash['reason'] == 'unauthorized'
    else
      # Ignore welcome / ping and keep waiting for confirmation
      next
    end
  end
end

#write(data) ⇒ Object

General write to the websocket



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# File 'lib/openc3/script/web_socket_api.rb', line 165

def write(data)
  subscribe()
  @stream.write(data)
end

#write_action(data_hash) ⇒ Object

Send an ActionCable command



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# File 'lib/openc3/script/web_socket_api.rb', line 149

def write_action(data_hash)
  # Subscribe first so the token is present in @identifier before we
  # serialize it below. ActionCable matches a 'message' command to its
  # subscription by the exact identifier string; if subscribe() injected the
  # token only afterward, the message identifier (no token) would not match
  # the subscription identifier (with token) and the server would silently
  # ignore the action.
  subscribe()
  json_hash = {}
  json_hash['command'] = 'message'
  json_hash['identifier'] = JSON.generate(@identifier, allow_nan: true)
  json_hash['data'] = JSON.generate(data_hash, allow_nan: true)
  write(JSON.generate(json_hash, allow_nan: true))
end